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Collared Forest Falcon
Micrastur semitorquatus

Status: Lower risk

Population Trend: Unknown.

Other Names: Collared Forest-falcon, Lesson's Hawk, Mexican Harrier Hawk, Micrastur melanoleucus, Pied Forest Hawk.

Micrastur semitorquatus
click to enlarge
Distribution: Neotropical. North-central MEXICO south through Central America and west of the Andes through COLOMBIA, ECUADOR, and PERU, and east of the Andes south through Amazonia to northern ARGENTINA and PERU. more....

Subspecies: 2 races. M. s. naso: North-central MEXICO (Sinaloa, Tamaulipas) south through Central America to northern and western COLOMBIA, western ECUADOR, and extreme northwestern PERU; M. s. semitorquatus: Eastern COLOMBIA east to the GUIANAS and south through eastern PERU, northern and eastern BOLIVIA and BRAZIL to PARAGUAY and northern ARGENTINA. more....

Taxonomy: Considered to include M. buckleyi by Hellmayr and Conover (1949), despite arguments advanced by Traylor (1948) that the latter form is a separate species, based on its smaller size and plumage differences. Amadon (1964) described the first female and immature specimens of M. buckleyi and agreed that M. semitorquatus and M. buckleyi are indeed separate species, a treatment that has been followed by all subsequent authorities.

Movements: Probably non-migratory.

Habitat and Habits: Found in lowlands and middle elevations to 2,500 m or higher and prefers the canopy of thickets in solid or broken forest, swamp forests, mangroves, late second-growth and scrub. Although it occurs mostly in heavily wooded regions, it is typically an edge species, occurring low in tangled thickets, and is rare in the interior of forests of large extent (Slud 1964, Thorstrom 2001). It does not soar. This large-eyed species calls before dawn and after dusk, sometimes from a partly exposed perch at the forest edge. Otherwise, it is furtive and difficult to spot, and it may be somewhat nocturnal. It often occurs in pairs, regardless of the season. It is inactive when not hunting and may rest lengthwise on a branch like a nightjar. more....

Food and Feeding Behavior: Feeds on large lizards, snakes, rodents, birds (up to the size of guans and ibises), and large insects. This species reportedly preys on domestic chickens. It hunts by ambush from a concealed perch, by flying from perch to perch, by running along large branches, or even running on the ground with amazing speed and agility. It hunts at dawn and dusk, made possible by its large eyes and possibly a well developed sense of hearing. It also follows army ant swarms to capture invertebrates flushed by the ants (Mays 1985), but far less often than the smaller Micrastur species (Willis et al. 1983). Smith (1969) auggested that in Panama the congeneric M. mirandollei and M. semitorquatus both deliberately emit high-pitched vocalizations to attract avian prey, and he was able to attract mobbing passerines to speakers by playing the calls of these forest falcons. In turn, these forest falcons are attracted to the sounds made by excited birds, or by imitations of such sounds (Slud 1964, Wetmore 1965). more....

Breeding: Nests are in cavities of various types, including natural tree cavities (Mader 1979, Guedes 1993, Thorstrom 2001, López-Lanús 2000, Carrara et al. 2007), a hole in a cliff (Baker et al. 2000), a cave (Vallejos et al. 2008), and in abandoned buildings (Cobb 1990, Carvalho et al. 2002). Competition with macaws for nest cavities in trees has been reported from Ecuador and Brazil. Clutch size is 1-3 (usually 2) white eggs, heavily spotted with tan, brown, and chocolate (Wetmore 1974, Thorstrom et al. 2000). Only the female incubates, and the male provides food until the middle of the nestling period, when the female also begins hunting and delivering prey to the young. At Tikal, the incubation period was 46-48 days at one nest, the nestling period was 50 days, and the whole breeding period lasted approximately 28 weeks from courtship to fledgling dispersal (Thorstrom et al. 2000). In one instance, Thorstrom et al. (2000) observed an extra-pair adult delivering food to young at week 4 of the post-fledging period. In the population studied at Tikal, no re-nesting was observed after a nest failure, and no territorial pair bred in consecutive years (Thorstrom et al. op cit.).more....

Conservation: Widespread and locally common in some areas, but generally regarded as uncommon, probably because it is often overlooked. Categorized globally as a species of "Least Concern" by BirdLife International (2009). more....

Important References: 
Bierregaard, R.O. 1994. Collared Forest-falcon. P. 254 in del Hoyo, J., A.
  Elliott, and J. Sargatal (eds). Handbook of birds of the world. Vol. 2. New
  World vultures to guineafowl. Lynx Edicions, Barcelona, Spain.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
López-Lanús, B. 2000. Collared Forest-falcon Micrastur semitorquatus
  courtship and mating, with take-over of a macaw nest. Cotinga 14:9-11.
Mader, W.J. 1979. First nest description for the genus Micrastur (forest
  falcons). Condor 81:320.
Mays, N.M. 1985. Ants and foraging behavior of the Collared Forest-falcon.
  Wilson Bulletin 97:231-232.
Mendes de Carvalho, E.P., and C.E. Alencar Carvalho. 1998. [Description of
  the nesting of Micrastur semitorquatus (Falconiformes: Falconidae) in the
  interior of rural habitat in the municipality of Sete Lagoas, Minas Gerais].
  Atualidades Ornitologicas 86:12. (In Portuguese)
Thorstrom, R. 2000. The food habits of sympatric forest-falcons during the
  breeding season in northeastern Guatemala. Journal of Raptor Research
Thorstrom, R.. 2001. Nest-site characteristics and breeding density of two
  sympatric forest-falcons in Guatemala. Ornitologia Neotropical 12:337-343.
Thorstrom, R. 2007. Home ranges of Barred (Micrastur ruficollis) and
  Collared Forest-falcons during the breeding season in Tikal National Park,
  Guatemala. Ornitologica Neotropical 18:395-405.
Thorstrom, R.K. 2012. Collared Forest Falcon. Pp. 250-254 in D.F. Whitacre
  (ed.), Neotropical birds of prey: biology and ecology of a forest raptor
  community. Cornell University Press, Ithaca, NY.
Thorstrom, R., J.D. Ramos, and J.M. Castillo. 2000. Breeding biology and
  behavior of the Collared Forest-falcon (Micrastur semitorquatus) in
  Guatemala. Ornitologia Neotropical 11:1-12.
Thorstrom, R., C.L. Turley, F.G. Ramirez and B.A. Gilroy. 1990.
  Description of nests, eggs, and young of the Barred Forest-falcon (Micrastur
) and of the Collared Forest-falcon (M. semitorquatus). Condor

Sites of Interest:
Collared Forest Falcon photos.
Aves de Rapina do Brasil
Species account with emphasis on Brazil.

Albuquerque, Jorge
Aldana, Fernando
Azevedo, Marcos Antônio Guimarães
Beers, Roy
Gómez, César
Quirós Bazán, Norman
Riba-Hernández, Laura
Santos, Kassius Klay
Shrum, Peggy
Thorstrom, Russell
Valdez, Ursula
Vargas G., José de J.
Whittaker, Andrew

Last modified: 7/27/2012

Recommended Citation: Global Raptor Information Network. 2021. Species account: Collared Forest Falcon Micrastur semitorquatus. Downloaded from http://www.globalraptors.org on 19 Apr. 2021

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